From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Response to a customer complaint regarding a repeatedly blowing field fuse on vehicle GXO-46, with diagnostic advice.
| Identifier | ExFiles\Box 47\3\ Scan115 | |
| Date | 3rd July 1931 | |
| To FN. from Hs{Lord Ernest Hives - Chair}/Pgt. c. Sg.{Arthur F. Sidgreaves - MD} Wor.{Arthur Wormald - General Works Manager} c. H.{Arthur M. Hanbury - Head Complaints} Hd.{Mr Hayward/Mr Huddy} Hs{Lord Ernest Hives - Chair}/Pgt2/AD3.7.31. CUSTOMER'S COMPLAINT. GXO-46. In reply to PM10/WT29.6.31, dealing with a complaint of repeated blowing of field fuse. We think that the cause is more likely to be a bad contact or connection in the main dynamo charging circuit and we suggest that this circuit, from the switchbox through the ammeter, main fuse, battery and cutout, to the dynamo negative brush, be carefully examined for this, giving special attention to the following points :- (1) The main negative brush. This may be worn or not properly clean on the surface and so not making good contact with the commutator. It may be sticking in the holder. To make sure, it would be advisable to clean it with a petrol moistened rag. (2) The cutout points should make good contact, and when closed, rub smoothly together. If at all pitted they should be cleaned or trimmed. (3) The connections to the battery, and also the cell to cell connections, should be cleared of any corrosion as this may have partly eaten through one of the connections. The fusing current of the cartridge fuse is between 6.0 and 7.5 amperes, while the field current, in the most extreme of normal conditions i.e. cold, and running direct on a fully charged battery, for the type of dynamo fitted to GXO-46, should not rise above 4.5 amperes. We have ascertained that GXO-46 was fitted with a normal output machine (No. P.8.P) and unless it has been changed since outside the Works, the dynamo output, under normal conditions, is beyond suspicion. A bad connection or contact as indicated above would, however, cause the output to be abnormally high, with a corresponding increase in field current and a clue might be obtained from an observation of the output previous to the fuse blowing. | ||